linux-kernel - [RFC PATCH for 6.13 v1 11/20] thermal: core: Separate code running under thermal_list

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Message-ID: <1822468.VLH7GnMWUR@rjwysocki.net>
Date: Sat, 14 Sep 2024 12:38:45 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM <linux-pm@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
 Daniel Lezcano <daniel.lezcano@...aro.org>,
 Lukasz Luba <lukasz.luba@....com>, Zhang Rui <rui.zhang@...el.com>
Subject:
 [RFC PATCH for 6.13 v1 11/20] thermal: core: Separate code running under
 thermal_list_lock

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

To prepare for a subsequent change that will switch over the thermal
core to using a mutex guard for thermal_list_lock management, move the
code running under thermal_list_lock during the initialization and
unregistration of cooling devices into separate functions.

While at it, drop some comments that do not add value.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/thermal/thermal_core.c |   64 +++++++++++++++++++++++------------------
 1 file changed, 36 insertions(+), 28 deletions(-)

Index: linux-pm/drivers/thermal/thermal_core.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_core.c
+++ linux-pm/drivers/thermal/thermal_core.c
@@ -959,6 +959,20 @@ static void thermal_zone_cdev_bind(struc
 		__thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
 }
 
+static void thermal_cooling_device_init_complete(struct thermal_cooling_device *cdev)
+{
+	struct thermal_zone_device *tz;
+
+	mutex_lock(&thermal_list_lock);
+
+	list_add(&cdev->node, &thermal_cdev_list);
+
+	list_for_each_entry(tz, &thermal_tz_list, node)
+		thermal_zone_cdev_bind(tz, cdev);
+
+	mutex_unlock(&thermal_list_lock);
+}
+
 /**
  * __thermal_cooling_device_register() - register a new thermal cooling device
  * @np:		a pointer to a device tree node.
@@ -981,7 +995,6 @@ __thermal_cooling_device_register(struct
 				  const struct thermal_cooling_device_ops *ops)
 {
 	struct thermal_cooling_device *cdev;
-	struct thermal_zone_device *pos;
 	unsigned long current_state;
 	int id, ret;
 
@@ -1048,16 +1061,7 @@ __thermal_cooling_device_register(struct
 	if (current_state <= cdev->max_state)
 		thermal_debug_cdev_add(cdev, current_state);
 
-	/* Add 'this' new cdev to the global cdev list */
-	mutex_lock(&thermal_list_lock);
-
-	list_add(&cdev->node, &thermal_cdev_list);
-
-	/* Update binding information for 'this' new cdev */
-	list_for_each_entry(pos, &thermal_tz_list, node)
-		thermal_zone_cdev_bind(pos, cdev);
-
-	mutex_unlock(&thermal_list_lock);
+	thermal_cooling_device_init_complete(cdev);
 
 	return cdev;
 
@@ -1268,38 +1272,42 @@ static void thermal_zone_cdev_unbind(str
 	__thermal_zone_cdev_unbind(tz, cdev);
 }
 
-/**
- * thermal_cooling_device_unregister - removes a thermal cooling device
- * @cdev:	the thermal cooling device to remove.
- *
- * thermal_cooling_device_unregister() must be called when a registered
- * thermal cooling device is no longer needed.
- */
-void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
+static bool thermal_cooling_device_exit(struct thermal_cooling_device *cdev)
 {
 	struct thermal_zone_device *tz;
-
-	if (!cdev)
-		return;
-
-	thermal_debug_cdev_remove(cdev);
+	bool ret = true;
 
 	mutex_lock(&thermal_list_lock);
 
 	if (!thermal_cooling_device_present(cdev)) {
-		mutex_unlock(&thermal_list_lock);
-		return;
+		ret = false;
+		goto unlock;
 	}
 
 	list_del(&cdev->node);
 
-	/* Unbind all thermal zones associated with 'this' cdev */
 	list_for_each_entry(tz, &thermal_tz_list, node)
 		thermal_zone_cdev_unbind(tz, cdev);
 
+unlock:
 	mutex_unlock(&thermal_list_lock);
 
-	device_unregister(&cdev->device);
+	return ret;
+}
+
+/**
+ * thermal_cooling_device_unregister() - removes a thermal cooling device
+ * @cdev: Thermal cooling device to remove.
+ */
+void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
+{
+	if (!cdev)
+		return;
+
+	thermal_debug_cdev_remove(cdev);
+
+	if (thermal_cooling_device_exit(cdev))
+		device_unregister(&cdev->device);
 }
 EXPORT_SYMBOL_GPL(thermal_cooling_device_unregister);